Models for Carbon-Rich Stars with Helium Envelopes
Abstract
Stellar models with carbon-rich interiors and helium envelopes of varying fractional mass have been constructed. The models have masses of 0.75, 1.02, and 1.37 M0. A few 1.02 M0 models with hydrogen-rich outer envelopes of small fractional mass have also been constructed. The evolution of these models is compared with the observed evolution of the nuclei of planetary nebulae (NPNs). Some models give good agreement with the luminosities and evolutionary time scales of NPNs, but the effective temperatures of these models are too high. We investigate the minimum mass required for carbon ignition in the stellar interior as a function of the fractional mass of the helium envelope. Subject headings: interiors, stellar - planetary nebulae - stellar evolution
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1973
- DOI:
- 10.1086/152059
- Bibcode:
- 1973ApJ...181..409J